S-1/A Files S-1: RSU & Capital Gains Tax Exposure Calculator — Aug 17, 2026

What Changed

Gravity Acquisition Corp. filed an amended S-1 registration statement on August 17, 2026. The filing signals an upcoming IPO or SPAC merger that will introduce new equity into public markets. For accredited investors holding concentrated positions in private tech or late-stage venture assets, this represents a liquidity event template worth modeling now.

The Numbers That Matter

Filing Detail	Value	Implication for HNW Investors
Filing Type	S-1/A (Amended)	Final pricing and allocation terms likely within 30 to 45 days
Document Size	4 MB	Comprehensive disclosure suggests complex capital structure or multi-party merger
Filing Date	August 17, 2026	Positions IPO window in Q4 2026, subject to market volatility and Fed policy timing
SPAC Structure	Gravity Acquisition Corp.	Existing public vehicle means faster execution than traditional IPO path

What This Means for Your Portfolio

If you hold equity in the target company, your lockup period begins at close and typically runs 180 days. On a $1M pre-IPO position vesting at a $15 share price, a 25% post-lockup decline costs you $250K in after-tax proceeds. Historical data shows 70% of SPACs trade below $10 within 12 months of merger close, which investors modeling concentration strategies should consider.

Scenario Analysis

Portfolio Exposure	Pre-IPO Equity Value	Post-Lockup Sale at -20%	Post-Lockup Sale at +30%	Net Tax Impact (Federal + State)
$500K position	$500K	$400K gross, $340K net	$650K gross, $533K net	15% federal long-term capital gains plus 13.3% CA top rate
$1M position	$1M	$800K gross, $680K net	$1.3M gross, $1.07M net	Same blended rate on gains over cost basis
$2M position	$2M	$1.6M gross, $1.36M net	$2.6M gross, $2.14M net	AMT risk if ISO exercise preceded IPO within 12 months

The Mechanics of SPAC Lockups

Traditional IPO lockups run 180 days from pricing. SPAC mergers often include tiered lockups with early release triggers tied to share price thresholds. If the stock trades above 150% of the $10 trust value for 20 of 30 trading days, some agreements allow partial releases at 90 days. This creates flexibility but also concentrates selling pressure if the threshold is hit early. Your cost basis determines whether you optimize for the first or second release window.

Tax Timing Considerations

If your equity vests as ISOs and you exercised within 12 months of the IPO, the spread between exercise price and FMV at vest counts as an AMT preference item. On a $1M position with a $3 exercise price and $15 IPO price, that is a $1.2M AMT add-back in 2026. If your total AMT liability exceeds regular tax by more than $50K, you trigger a multi-year credit carryforward. The math changes entirely if you exercised more than 12 months pre-IPO and qualify for long-term capital gains treatment at sale.

Secondary Market Implications

SPACs trade publicly before merger close. If you hold warrants or founder shares in Gravity Acquisition itself, you can access liquidity now at a discount to the $10 trust value. Current SPAC warrant prices average $0.60 to $1.20 depending on deal timeline and sponsor reputation. For a $500K warrant position, that spread represents $200K to $400K in immediate liquidity versus waiting for merger close and subsequent lockup expiration.

Frequently Asked Questions

Q: How does a SPAC lockup differ from a traditional IPO lockup for employee equity? A: SPAC lockups often include price-based early release triggers at 90 or 120 days, while traditional IPO lockups are fixed at 180 days with no early exit.

Q: What is the tax treatment of SPAC warrants received as part of a founder or employee equity package? A: Warrants received for services are taxed as ordinary income at vest based on fair market value, then as capital gains or losses at exercise or sale.

Q: If I sell shares immediately after lockup expires, what is my effective tax rate on gains? A: Federal long-term capital gains rates, net investment income tax, and state tax vary by location and income level. In California, combined rates for high-income earners can approach 37%, while in Texas (which has no state income tax) federal rates apply. Consult a tax professional for your specific situation.

Q: Should I hedge a concentrated SPAC position during lockup using options? A: Hedging with protective puts may trigger constructive sale rules under IRC 1259 if delta exceeds 70%, converting unrealized gains to current-year taxable income.

Disclaimer

This article is for informational purposes only and does not constitute professional financial, tax, or legal advice. Before making investment decisions, consult with a qualified financial advisor, tax professional, or attorney regarding your specific situation.

Run the Numbers

Use CalcMoney's Calculate Your After-Tax RSU Proceeds to model your exact exit value across multiple sale dates and price scenarios under current federal and state tax rates.

Run the Numbers: Capital Gains Tax Terminal on CalcMoney — see your exact figures under current market conditions.

Data sourced from SEC EDGAR S-1 Filings (IPO). Rates and thresholds are for informational purposes only. Consult a licensed financial advisor before making mortgage, investment, or tax decisions.

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